Note 11 - Earnings Per Common Share - Reconciliation of Basic to Diluted Weighted Average Shares Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2025		Sep. 30, 2025		Jun. 30, 2025		Mar. 31, 2025		Dec. 31, 2024		Sep. 30, 2024		Jun. 30, 2024		Mar. 31, 2024		Dec. 31, 2025	Dec. 31, 2024
Net income																	$ 755	$ 522
Less: Net income attributable to non-controlling interests																	67	90
Net income attributable to LGL Group common stockholders																	$ 688	$ 432
Weighted average common shares outstanding - basic (in shares)	5,547,516	[1]	5,312,797	[1]	5,352,937	[1]	5,352,937	[1]	5,352,937		5,352,937		5,352,937		5,352,937		5,404,463	5,352,937
Warrants (in shares)																	985,778	192,310
Restricted stock (in shares)																	15,775	8,576
Weighted average common shares outstanding - diluted (in shares)	5,547,516		5,649,743		5,352,937		5,352,937		5,577,062		5,531,969		5,482,543		5,604,430		6,406,016	5,553,823
Basic (in dollars per share)	$ (0)	[1]	$ 0.15	[1]	$ (0.01)	[1]	$ (0)	[1]	$ 0.04	[1]	$ 0.01	[1]	$ 0.03	[1]	$ 0	[1]	$ 0.13	$ 0.08
Diluted (in dollars per share)	$ (0)	[1]	$ 0.14	[1]	$ (0.01)	[1]	$ (0)	[1]	$ 0.04	[1]	$ 0.01	[1]	$ 0.02	[1]	$ 0	[1]	$ 0.11	$ 0.08

[1] Basic and diluted earnings per share are calculated using actual, unrounded amounts. Therefore, the quarterly earnings per share may not sum to the earnings per share on the Consolidated Statements of Operations.